#include <iostream>
using namespace std;

int main(int argc, char const *argv[])
{
    string str;
    cout<<"请你输入一个字符串:"<<endl;
    cin>>str;
   
    for (int i = 0; i < str.length(); i++)
    {
        for (int j = i+1; j < str.length(); j++)
        {
            if (str.at(i) == str.at(j))
            {
                str.erase(j,1);
                j--;
            }
            
        }
        
    }
    
    cout<<str<<endl;

    return 0;
}
